Quaternary compounds or compounds including four elements such as Ba.sub.2 SrWO.sub.6 and Ba.sub.2 CaAl.sub.2 O.sub.6 have been used heretofore as impregnants in the manufacture of high current density cathodes. One of the difficulties with these compounds as cathode impregnants has been their lack of superior emissive characteristics. This has been largely due to the lack of certain emission improving elements such as osmium, iridium and rhenium within the impregnant.